Default name for the credentials cache file, in the form type:residual. The type of the default cache may determine the
availability of a cache collection. For instance, a default cache
of type DIR causes caches within the directory to be present
in the global cache collection.

Filename for trace-logging output (introduced in release 1.9).
For example, envKRB5_TRACE=/dev/stdoutkinit would send
tracing information for kinit to /dev/stdout. Some programs
may ignore this variable (particularly setuid or login system
programs).